Apparatus for forming a self-supporting ale of metal cans comprising a baler adapted to compact metal cans into a bale. Opposite side walls of the baler include an array along each side wall of parallel open-face grooves. A platen having defined along each of its opposite sides walls, an array of projections adapted to be received within respective ones of the wall grooves in meshing relationship whereby movement of the platen along the length of the baler functions to compact the cans disposed within the grooves to a higher degree of densification than the degree of densification of cans proximate the central portions of the bale.